Preferred Language
Articles
/
PBfA2o0BVTCNdQwCYyea
Fabrics-Shear Strength Links of Silicon-Based Granular Assemblies
...Show More Authors
ABSTRACT<p>Silicon (Si)-based materials are sought in different engineering applications including Civil, Mechanical, Chemical, Materials, Energy and Minerals engineering. Silicon and Silicon dioxide are processed extensively in the industries in granular form, for example to develop durable concrete, shock and fracture resistant materials, biological, optical, mechanical and electronic devices which offer significant advantages over existing technologies. Here we focus on the constitutive behaviour of Si-based granular materials under mechanical shearing. In the recent times, it is widely recognised in the literature that the microscopic origin of shear strength in granular assemblies are associated with their ability to establish anisotropic networks (fabrics) comprising strong-force transmitting inter-particle contacts under shear loading. Strong contacts pertain to the relatively small number of contacts carrying greater than the average normal contact force. However, information on how such fabrics evolve in Si-based assemblies under mechanical loading, and their link to bulk shear strength of such assemblies are scarce in the literature. Using discrete element method (DEM), here we present results on how Si-based granular assemblies develop shear strength and their internal fabric structures under bi-axial quasi-static compression loading. Based on the analysis, a simple constitutive relation is presented for the bulk shear strength of the Si-based assemblies relating with their internal fabric anisotropy of the heavily loaded contacts. These findings could help to develop structure-processing property relations of Si-based materials in future, which originate at the microscale.</p>
Scopus Clarivate Crossref
View Publication
Publication Date
Sun Dec 01 2019
Journal Name
Al-khwarizmi Engineering Journal
Effect of Laser Shock Peening on the Fatigue Behavior and Mechanical Properties of Composite Materials
...Show More Authors

In this study, Laser Shock Peening (LSP) effect on the polymeric composite materials has been investigated experimentally. Polymeric composite materials are widely used because they are easy to fabricate and have many attractive features. Unsaturated polyester resin as a matrix was selected and Aluminum powder with micro particles as a reinforcement material was used with different volume fraction (2.5%, 5% and 7.5%). Hand lay-up process was used for preparation the composites. Fatigue test with constant amplitude with stress ratio (R =-1) was carried out before and after LSP process with two levels of energy (1Joule and 2Joule). The result showed an increase in the endurance strength of 25.448% at 7.5% volume fraction when peened is 1J

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Jul 01 2008
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
KEYS FOR IDENTIFICATION FOR GENERA AND SPECIES OF THRIPS (THYSANOPTERA : THRIPIDAE) FROM MIDDLE OF IRAQ
...Show More Authors

Keys for 22 species representing ten genera Thripidae collection carried out during 1999-2001 in different localities in the middle of Iraq. Of them four species are described as new to science, Frankliniella megacephala sp. nov; Retithrips bagdadensis sp. nov; Chirothrips imperatus sp. nov; Taeniothrips tigridis sp. nov; Another thirteen species are recorded for the first time in Iraq; Thrips meridionalis (Pri.); Microcephalothrips abdominils (Crawford); Scolothrips pallidus (Beach); Scritothrips mangiferae Pri.; Frankliniella tritici Bagnall; Frankliniella schultzie Trybom; Frankliniella unicolor Morgan; Retithrips aegypticus Mar

... Show More
View Publication Preview PDF
Publication Date
Sat Dec 01 2018
Journal Name
Al-khwarizmi Engineering Journal
The Effect of Walled Nano-Carbon on the Physical, Thermal and Mechanical Properties of Epoxy
...Show More Authors

The physical, the thermal and the mechanical properties of Nano-composites, that consisted of Polyprime EP epoxy that reinforced by multi-walled carbon nanotubes (MWCNTs), have been studied. Various loading ratios, 0.1, 0.5, and 1 wt. %of MWCNT shave been infused into epoxy by a magnetic stirrer and then the hardener mixed with the mthat supplied with the epoxy. All sample shave been cutting using CNC machine. Tensile test, three-point bending, hardness tests, lee's disk, differential scanning calorimetry, water absorption and dielectric and electrical conductivity test were utilized on unfilled, MWCNT-filled epoxy to identify the loading effect on the properties of materials. Scanning electron microscopy (SEM) was used to determine the

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sat Jan 05 2019
Journal Name
Iraqi Journal Of Physics
Influence of chemical and thermal treatment on the purity of silica extracted from rice husk
...Show More Authors

In this work, chemical and thermal treatment were used to enhance silica extract on the purity of rice husk and to reduce the impurities associated with the extraction of silica. The thermal degradation of rice husk was studied. The characteristics and thermal degradation behavior of rice husk which investigated using thermogravimetric analyzer (TGA). Hydrochloric acid was used to soak the rice husk and the study of leaching influence is followed by XRF tests for samples before and after the combustion process. Acid treatment and combustion method seem to have a clear effect on silica purity. The pyrolysis processes were carried out at Laboratory temperature up to 650 oC in the presence of nitrogen gas flowing at 150 ml/min. The effect o

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Sun Jan 13 2019
Journal Name
Iraqi Journal Of Physics
Measurement of background radiation, cosmic ray flux and their hazard parameter of Baghdad city districts
...Show More Authors

The aim of this work was directed to measure the cosmic ray (CR)
flux and the background (BG) absorbed dose rate for districts of
Baghdad city. The maximum values of CR flux was 2.01
(particle/cm2.s) registered for several Baghdad districts and the
minimum was 0.403 (particle/cm2.s) belonging to Al-kadhimiya
district, whereas the overall average value was 1.24 (particle/cm2.s).
The BG measurements showed that the maximum absorbed dose was
25 nSv/h belonging to Noab AL-Dhbat district and the minimum
absorbed was 19.01 nSv/h observed in Al-Ghadeer district, while
the overall average was 22.56 nSv/h, and this value is small than the
Iraqi permissible limit, which is restricted by Iraqi Center of
Radiation Pr

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Jun 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
Crisis management effective of business organizations in the era of managerial technique: a philosophical study
...Show More Authors

At a time of increasing human potential in the face of crises and risks through the use of technology on a large scale and steadily in various fields of life, and the vulnerability of business organizations as a result of mistakes. The failure of a sudden these errors or omissions or symptoms. Also, some crises occur outside the control of management, others caused by leakage of important information and sometimes secret may be a strategy or a new plan or new project occurs outside the organization to the opposite of what is planned. Therefore, the crisis management are critical to all organizations, because the active management of the crisis helps to ensure the continued prosperity of the organization. Here comes from the resea

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Jun 03 2018
Journal Name
Baghdad Science Journal
Gene Expression and Polymorphism of Interleukin-4 in a Sample of Iraqi Rheumatoid Arthritis Patients
...Show More Authors

It was aimed to understand the interleukin-4 (IL-4) role in etio-pathogenesis of rheumatoid arthritis (RA). Two approaches were adopted. In the first one, a quantitative expression of IL4 gene was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and such findings were correlated with some demographic, clinical and laboratory parameters, which included gender, duration of disease, disease activity score (DAS-28), rheumatoid factors (RFs), C-reactive protein (CRP) and anti-cyclic citrullinated peptide (ACCP) antibodies. In the second approach, a single nucleotide polymorphism (SNP) of IL4 gene (rs2243250) was inspected by DNA sequencing using specific primers. Fifty-one Iraqi RA patients (22 males and 29 fem

... Show More
View Publication Preview PDF
Scopus (11)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Sun Jan 13 2019
Journal Name
Iraqi Journal Of Physics
Plasma characteristics of Ag:Al alloy produced by fundamental and second harmonic frequencies of Nd:YAG laser
...Show More Authors

In this work, the spectra for plasma glow produced by pulse
Nd:YAG laser (λ=532 and 1064nm) on Ag:Al alloy with same molar
ratio samples in distilled water were analyzed by studying the atomic
lines compared with aluminum and silver strong standard lines. The
effect of laser energies of the range 300 to 800 mJ on spectral lines,
produced by laser ablation, were investigated using optical
spectroscopy. The electron temperature was found to be increased
from 1.698 to 1.899 eV, while the electron density decreased from
2.247×1015 to 5.08×1014 cm-3 with increasing laser energy from 300
to 800 mJ with wavelength of 1064 nm. The values of electron
temperature using second harmonic frequency are greater than of<

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Sun Mar 27 2022
Journal Name
Sport Tk-revista Euroamericana De Ciencias Del Deporte
Effect of resistance training on the biomechanics and accuracy of serve receiving skills in volleyball
...Show More Authors

This study aimed to identify the effect of resistance training on the biomechanics and accuracy of serve receiving skills in volleyball. The research community was composed of 26 young volleyball players of Baghdad volleyball clubs. A total of 4 players were selected for the preliminary experiment, while 14 participants were recruited as the main sample for the study. In the present study, a set of resistance exercises were designed by the researchers for the volleyball players of the sample. Exercises were performed by the sample participants during the course of study. The biomechanical variables considered in the present study were: Preparation moment (shoulder joint angle, hip angle, knee joint angle), moment of pr

... Show More
View Publication
Scopus (5)
Crossref (3)
Scopus Crossref
Publication Date
Fri Dec 06 2019
Journal Name
Mechanics Of Advanced Materials And Structures
Finite element modeling of RC gable roof beams with openings of different sizes and configurations
...Show More Authors

View Publication Preview PDF
Scopus (10)
Crossref (8)
Scopus Clarivate Crossref